The present invention concerns a procedure and a device for processing combustion gases, and more particularly a procedure and a device for the depollution of combustion gas.
During the combustion of fuels such as gasoline or gas-oil a great number of components are produced such as nitrogen oxide (NOx), carbon monoxide (CO), and the hydrocarbons (HC). To this is added the ozone (O3), a secondary pollutant formed by photochemical reactions between the nitrogen oxide and the hydrocarbons.
Public institutions have encouraged research in order to reduce these harmful emissions and many devices have been proposed. We know, in the automobile field, the use of the catalyst, whose action is to burn the harmful substances.
Unfortunately the catalyst only reduces certain emissions, and on the contrary transforms certain components in even more dangerous substances.
Other solutions have been presented particularly in the industrial field with the use of water filters in the chimney conducts to capture and recover toxic substances in the water. This water is re-processed in order to separate it from these substances and then re-injected in the filter circuit.
Although a certain improvement of the quality of the air has been registered thanks to the use of these depollution devices, the latter present gaps, either in their installation or in their cost or efficiency.
The objective of the present invention is to propose a procedure and a device that eliminates 100% of the most toxic substances, at the same time not generating any other harmful substance.
This objective is totally achieved by the depollution device of combustion gases of the present invention, characterised in that this device comprises a cooling chamber of the gases at a low temperature.
According to the invention, the procedure consists in depolluting the combustion gases by cooling them at a low temperature.
The depollution effect is obtained by the condensation of the polluting substances in a chamber where the gases are cooled at a temperature of a few degrees above zero. The condensation effect is produced when the gases are cooled, understanding that the lower the temperature the more the effect is increased.
The optimal temperature of condensation is near zero degrees Celsius, preferably between 3 and 6xc2x0 C., that is, just before ice crystals are formed. In fact, the formation of ice would have as a consequence the rapid obstruction of the exhaust.
The condensation liquid is then recovered for its ecological elimination.
This type of device can be used in a great number of installations, for example on the incineration factory chimneys, as well as for other applications of industrial chimneys, even in the field of vehicles with internal combustion engines.
In this last field, the present invention extends also to a cold production device (for example air conditioning) by recovering the thermal energy of the exhaust gases of the vehicle.
Such devices are described in the state of the art, particularly in the document GB-A-1357034 which describes a depollution device of the combustion gases according to the preamble of claim 1.
Although the main objective of this invention is the depollution of combustion gases, the invention is also understood as a system performing for the production of cooling energy by recovering the thermal energy of the combustion gases.
In order the cool the exhaust gases an evaporator is used placed in the exhaust box, which substantially cools said gases. Recuperators placed along the evaporator collect the condensation liquid. This liquid can either be ecologically eliminated at a rythm equivalent to the emptying of the engine oil or be reinjected in the receiver. In fact, due to its low quantity of production its mixing with gasoline or gas-oil causes no problem.
In a particular embodiment of the invention, the mixture coolant/absorbent used for the thermal cycle is a mixture of water (the absorbent) and ammonia (the coolant). The latter presents a good expansion property, an essential characteristic in this type of use. Trials have shown that with more than 70% of water in the mixture the cycle does not function any more in an optimal way.